The kiln hood seal was reformed by using positive pressure airtight sealing device during maintenance. The positive pressure airtight sealing device has the advantages of simple structure and convenient installation, which can effectively prevent sand and dust, reduce air leakage coefficient, avoid cylinder deformation and long service life of parts. The transformation took only 7 days to be successfully completed. After the transformation, it completely solved the soot emission problem of kiln head under positive pressure, put an end to the phenomenon of air leakage.  The standard coal consumption was reduced by 0.3kg/t.cl, the power consumption was reduced by 0.05~0.10kW·h/ t.cl, and the transformation achieved a good transformation effect.